The thread title says present perfect but your question is about past perfect.
"Within minutes of receiving the bomb threat, we had evacuated the building."

Use of past perfect in this sentence emphasizes the fact that the evacuation was completed by a certain time. The act of evacuation may have started within seconds and required several minutes to complete, but "had been" completed in the specified time frame.

You could use simple past tense, as follows:
"Within minutes of receiving the bomb threat, we evacuated the building."
The meaning would be similar but slightly different. It could imply that nothing happened until minutes later, then the we evacuated, and the evacuation didn't require any time at all.
The use of "within minutes" makes this a little fuzzy and blurs the distinction between past and past perfect. The difference would be clearer in a sentence like this.
Past perfect "Five minutes after the bomb threat we had evacuated the building."
Past tense: "Five minutes after the bomb threat we evacuated the building."
The sentence in past perfect would mean that we started evacuating some time before 5 minutes, and completed the evacuation within 5 minutes. The sentence in past tense would mean that we did nothing until 5 minutes later, then we evacuated.

Past perfect "Five minutes after the bomb threat we had evacuated the building."

So, first we evacuated, then five minutes passed

Am I right?

No. First there was a bomb threat. Then we evacuated the building. Then 5 minutes after the bomb threat, there was nobody left in the building.

There are a lot of ways this could happen. Maybe we started to evacuate 1 minute after the bomb threat, and completed it 2 minutes after the bomb threat. Maybe we started to evacuate 4 minutes after the bomb threat, and completed the evacuation within 1 minute. All we know from this sentence is that, at a time 5 minutes after the bomb threat, the evacuation was complete.